OBJECTIVES: Endocarditis in patients with ascending aortic prosthetic graft (AAPG) is a life-threatening complication. The purpose of this study was to examine the clinical presentation and prognosis of patients with AAPG endocarditis included in a large prospective infectious endocarditis multicentre study. METHODS: From January 2008 to April 2015, 3200 consecutive patients with infectious endocarditis according to the modified Duke criteria, were prospectively included in the 'Spanish Collaboration on Endocarditis Registry (GAMES)' registry. Twenty-seven definite episodes of endocarditis (0.8%) occurred in patients with AAPG. RESULTS: During the study period, 27 cases of endocarditis were detected in patients with AAPG. The median age of patients was 61 years [interquartile range (IQR) 51-68 years] and 23 (85.2%) patients were male. The median time from AAPG surgery to the episode of AAPG infection was 24 months (IQR 6-108 months). The most frequently isolated micro-organisms were coagulase-negative staphylococci and S. aureus (11 patients, 40.7%). Four patients (14.8%) underwent medical treatment, whereas surgery was performed in 21 (77.7%). Two patients (7.4%) died before surgery could be performed. The median hospital stay prior to surgery was 7 days (IQR 4-21 days). Surgery consisted of replacing previous grafts with a composite aortic graft (10 cases) or aortic homograft (2 patients), and removal of a large vegetation attached to the valve of a composite tube (1 case). Nine patients had an infected aortic valve prosthesis without evidence of involvement of the AAPG. Isolated redo-aortic valve replacement was performed in 8 (88.9%) of these patients. Reinfection occurring during 1 year of follow-up was not detected in any patient. Two patients (7.4%) died while awaiting surgery and 6 did so after surgery (22.2%). A New York Heart Association (NYHA) Class IV was associated with mortality in patients undergoing surgery (P < 0.019). CONCLUSIONS: Most cases of endocarditis in patients with AAPG occur late after initial surgery. Mortality rate of patients with AAPG endocarditis who undergo surgery is acceptable. NYHA Class IV before surgery is associated with an increased postoperative mortality.